Yet another gun threat against Cambridge middle schools

For the fourth time in a month - and the third time this week - Cambridge schools are on high alert. Cambridge Public Schools posted this morning:

Early Friday morning, the Cambridge Police Department notified the Cambridge Public Schools of another anonymous email threat for Friday, December 4, 2015. This is another threat of gun violence and it is directed at “cambridge mass middle schools.” Once again we are taking the threat seriously, proceeding with the utmost caution, and informing the public.

Police swept schools this morning and had officers stationed in the schools throughout the day. Students were only allowed to enter through the main doors. This is the same procedure officials followed after yesterday's threat - and the one last month.